I actually would have loved if there was a real greek legal case for this, like we could just say "Lycurgus vs. Theseus" and it actually meant something.

That's not what Google v Oracle was about. That case was about whether the API of a piece of code (in this case, the API of most of the Java standard library) is copyrightable as a whole, without the implementation; and subsequently, even if they are copyrightable, whether a new implementation of that API would be fair use.

In the end the conclusion from the SC was that Google's use was fair use regardless of the question of copyrightability, which they didn't decide on (the previous court, at Oracle's appeal, had found that APIs are in fact copyrightable and that Google's use did not fall under fair use of that copyrighted API as they weren't 100% compatible with other JVMs).

IIRC Google were scrupulous about ensuring there was no possiblity that the implementation might be derived from the original.

Is there a more relevant case you can cite? I’m fully aware of the differences, but its still relevant case law on how the US legal system would approach a case on this issue.